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WO2025202333A1 - Procédé respectueux de l'environnement permettant d'éliminer l'uranium et/ou le scandium de ressources contenant du nickel et/ou du cobalt - Google Patents

Procédé respectueux de l'environnement permettant d'éliminer l'uranium et/ou le scandium de ressources contenant du nickel et/ou du cobalt

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Publication number
WO2025202333A1
WO2025202333A1 PCT/EP2025/058339 EP2025058339W WO2025202333A1 WO 2025202333 A1 WO2025202333 A1 WO 2025202333A1 EP 2025058339 W EP2025058339 W EP 2025058339W WO 2025202333 A1 WO2025202333 A1 WO 2025202333A1
Authority
WO
WIPO (PCT)
Prior art keywords
uranium
scandium
cobalt
nickel
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2025/058339
Other languages
English (en)
Inventor
Werner VERDICKT
Willem VEREYCKEN
Joris ROOSEN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Umicore NV SA
Original Assignee
Umicore NV SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from EP24167018.1A external-priority patent/EP4624602A1/fr
Application filed by Umicore NV SA filed Critical Umicore NV SA
Publication of WO2025202333A1 publication Critical patent/WO2025202333A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
    • C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B23/00—Obtaining nickel or cobalt
    • C22B23/04—Obtaining nickel or cobalt by wet processes
    • C22B23/0407—Leaching processes
    • C22B23/0415—Leaching processes with acids or salt solutions except ammonium salts solutions
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B23/00—Obtaining nickel or cobalt
    • C22B23/04—Obtaining nickel or cobalt by wet processes
    • C22B23/0453—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B23/0461—Treatment or purification of solutions, e.g. obtained by leaching by chemical methods
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B59/00—Obtaining rare earth metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
    • C22B60/02—Obtaining thorium, uranium, or other actinides
    • C22B60/0204—Obtaining thorium, uranium, or other actinides obtaining uranium
    • C22B60/0217—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to the processing of nickel- and/or cobalt-containing resources to obtain aqueous salt solutions comprising nickel and/or cobalt with reduced uranium and/or scandium content, which can be used in various industries such as stainless-steel production, electroplating, and batteries.
  • Uranium is a naturally occurring element that is often found in small concentrations in many types of rocks and that is commonly present in the feedstock used in the production of various metals. For instance, nickel and cobalt are often extracted from ores that also contain uranium. However, as uranium is a radioactive element, it is crucial to sequester it during the processing of nickel-containing raw materials to prevent potential harm to human health and the environment. Therefore, developing efficient methods to remove or reduce the amount of uranium in nickel-containing feedstocks is a critical area of research and development.
  • scandium is often present in ores that are used for nickel and cobalt extraction and is an undesired impurity in nickel and/or cobalt aqueous product salt solutions.
  • a method for removing uranium from nickel-containing feedstocks using ion exchange resins has been proposed by Kiegiel, K. et al. Kiegiel, K., Abramowska, A., Bieluszka, P., Zakrzewska-Koltuniewicz, G., & Wolkowicz, S. "Solvent extraction of uranium from leach solutions obtained in processing of Polish low-grade ores.” Journal of Radioanalytical and Nuclear Chemistry, 311, 589-598, 2017, https://doi.org/ 10.1007/S10967-016-5029-5.
  • the method provides a simple alternative to methods such as solvent extraction, ion exchange, and microbial processes. Yet, the effectiveness of the proposed method may depend on the specific properties of the feedstocks and the ion exchange resins used, and the scalability of the method for industrial applications may require further research and development.
  • WO20101 18455 provides a method for the treatment of mixed hydroxide product (MHP) produced in a metal extraction process such as a nickel extraction process.
  • the method comprises the steps of treating the MHP with a first acid solution at a pH in the range of 4 to 8 as a first redissolution step and separating a first liquor formed in the first redissolution step from a first residue formed in this step.
  • the method further comprises the step of treating the first residue with a second acid solution at a pH in the range of 0.5 to 4 as a second redissolution step.
  • the first solvent extraction step is used for the quantitative removal of zinc, uranium as well as some calcium and manganese.
  • GB759900A describes the selective precipitation of uranium from solutions thereof containing other metals by adjustment of the pH in the presence of a soluble phosphate or arsenate.
  • a solution containing U, Fe, Al, Zn and Co sulphates and having an Al/U ratio of 1 : 1 was treated with calcium hydroxide to a pH of 3.1 whereby basic ferric sulphate precipitated, the pH falling to 2.8.
  • Phosphoric acid was added and the pH adjusted to 2.5 with calcium hydroxide, thereby precipitating the uranium.
  • W02022090628A1 discloses a system for removing uranium from a cobalt-rich raffinate.
  • the system comprises: a copper precipitation circuit for processing the cobalt- rich raffinate into a copper precipitate, arranged to receive phosphoric acid from a phosphoric acid storage to precipitate uranium included in the cobalt-rich raffinate; a copper thickener circuit for processing the copper precipitate into a first flow that comprises copper hydroxide and precipitated uranium and a second flow that comprises a cobalt sulphate solution and residual phosphoric acid; a measurement device for measuring a quantity that is representative of an amount of residual phosphoric acid in the second flow; and a control system for regulating a dosage of phosphoric acid introduced to the copper precipitation circuit in dependence of said measured quantity in view of a target amount of residual phosphoric acid.
  • Such methods relying on precipitation of uranium and/or scandium with phosphoric acid require high excess usage of the phosphate compound to remove uranium and/or scandium from the solutions to a low ppm level, and therefore suffer from a loss of valuable nickel and/or cobalt atoms via the uranium and/or scandium precipitate. Further, such methods strongly rely on monitoring and control systems to ensure the correct dosage of phosphoric acid. Therefore, there is a need for more effective, efficient, and sustainable methods for removing uranium and/or scandium from feedstocks. Such methods should be cost-effective, environmentally friendly, and produce minimal waste streams. In addition, the methods should be applicable to a wide range of feedstocks and applicable to different industries.
  • the current invention provides in a solution for at least one of the above-mentioned problems by providing a method for efficient removal of uranium and/or scandium from nickel- and/or cobalt-containing resources to produce nickel and/or cobalt salt solutions, as described in claim 1.
  • the present invention is advantageous because it provides a simple and efficient method for preparing an aqueous solution comprising nickel and/or cobalt that has a significantly reduced uranium and/or scandium content.
  • the method involves a series of steps including leaching a solid material feed comprising nickel and/or cobalt and uranium and/or scandium with a mineral acid in an aqueous medium, increasing the pH of the leachate solution to precipitate iron and aluminium, if present, and adding a phosphate compound to form a uranium and/or scandium precipitate.
  • the method includes a solvent-extraction step to remove remaining traces of uranium and/or scandium.
  • the method is applicable to various solid material feeds, including MHP and CHIP.
  • the current invention for removing uranium and/or scandium from a nickel- and/or cobalt-based feedstock including two steps of uranium and/or scandium removal offers advantages over alternative methods only making use of solvent extraction, ion exchange, or precipitation with a phosphate compound in several ways.
  • the proposed method is relatively simple and straightforward, involving only a few steps to remove most of the uranium and/or scandium, namely leaching with a mineral acid, increasing pH, and adding a stoichiometric excess of a phosphate compound to precipitate uranium and/or scandium.
  • the "selectivity" S of an extractant for one metal over another metal can be expressed as the ratio of the distribution coefficients D for both metals:
  • M is a metal, such as nickel or uranium or scandium, 0 refers to the organic phase and A refers to the aqueous phase.
  • O/A ratio refers to the volume ratio of organic phase (0) to aqueous phase (A) used for solvent extraction or solvent stripping.
  • the general inventive concept of the present invention consists of a process for preparing nickel and/or cobalt salt solutions, said process comprising the steps of: i. leaching a solid material feed comprising uranium and/or scandium, and at least 20 wt% of at least one of nickel and cobalt relative to the total dry weight of the solid material feed, with a mineral acid in an aqueous medium, thereby obtaining a leachate solution comprising uranium and/or scandium ions, respectively, and at least one of nickel ions and cobalt ions, respectively; ii.
  • uranium and/or scandium precipitating at least in part uranium and/or scandium, respectively, by adding a phosphate compound and bringing the pH of said leachate solution to at least 2.5, and separating the precipitate from the aqueous medium; iii. extracting the remaining uranium and/or scandium, respectively, from the aqueous filtrate obtained in step ii. into an organic phase comprising an extractant and a diluent, thereby obtaining an aqueous raffinate comprising at least one of nickel ions and cobalt ions, respectively.
  • a leachate solution comprising uranium and scandium is obtained in step i
  • uranium and scandium are precipitated in step ii.
  • uranium and scandium are extracted in step iii.
  • a solid feed material may comprise at least 1 ppm of uranium based on the dry weight of said solid feed material.
  • a solid feed material may comprise at least 1 ppm of scandium based on the dry weight of said solid feed material.
  • the method according to the current invention has the advantage that uranium and/or scandium only exits the process via the uranium and/or scandium precipitate that can be easily filtered and separated from the leachate, allowing for efficient recovery and further processing of uranium and/or scandium, respectively.
  • the uranium and/or scandium precipitation can be performed in an efficient way, limiting the required excess of phosphate compounds, because trace amounts of uranium and/or scandium are further purified from the solution via solvent extraction.
  • the process according to the invention is performed in a way that the extraction capacity of the solvent to remove also other impurities is preserved. This is enabled by stripping of uranium and/or scandium from the solvent with highly concentrated acid, whereby the eluate containing uranium and/or scandium can be recycled to the first step of the process.
  • the present invention provides a unique and effective process that minimizes the use of hazardous chemicals, maximizes the recovery of uranium, scandium, nickel and cobalt, and produces a nickel- and/or cobalt-rich solution with low uranium and scandium content.
  • the present invention provides a process for preparing nickel and/or cobalt salt solutions, said process comprising the steps of: i. leaching a solid material feed comprising uranium and/or scandium, at least 20 wt% of at least one of nickel and cobalt, and at least 0.05 wt% of at least one of iron and aluminium, relative to the total dry weight of the solid material feed, with a mineral acid selected from the group consisting of H2SO4, HCI and HNO3 in an aqueous medium, thereby obtaining a leachate solution comprising uranium and/or scandium ions and at least one of nickel ions and cobalt ions, respectively; ii.
  • step iii. simultaneous or subsequent to step ii., adding a phosphate compound to the basified leachate solution in step ii. to form a uranium and/or scandium precipitate, respectively; iv. separating the precipitate formed in step iii. from the leachate solution, thereby obtaining an aqueous solution comprising uranium and/or scandium, respectively, and at least one of nickel ions and cobalt ions, respectively; and v.
  • the process involves leaching a solid material feed comprising uranium and/or scandium, at least one of nickel and cobalt, and at least one of iron and aluminium, with a mineral acid selected from the group consisting of H2SO4, HCI, and HNO3 in an aqueous medium, thereby obtaining a leachate solution comprising uranium and/or scandium ions and nickel- and/or cobalt-ions, respectively.
  • This leaching step is performed to dissolve, if present, uranium, scandium, nickel, cobalt, iron and aluminium in the solid material feed into the solution.
  • the leachate solution is then subjected to a series of steps to remove, or at least reduce the amount of uranium and scandium, if present in the leachate solution by forming a uranium and/or scandium precipitate and performing solvent extraction of uranium and/or scandium, respectively.
  • Figure 1 illustrates a preferred embodiment according to the current invention for a solid material feed comprising uranium, whereby in step i. a leachate solution comprising uranium is obtained, in step iii. a uranium precipitate is obtained, in step iv. an aqueous solution comprising uranium is obtained, and in step v. a uranium-en- riched organic phase is obtained.
  • Figure 3 shows a preferred embodiment according to the current invention for a solid material feed comprising scandium, but no uranium, whereby in step i. a leachate solution comprising scandium is obtained, in step iii. a scandium precipitate is obtained, in step iv. an aqueous solution comprising scandium is obtained, and in step v. a scandium-enriched organic phase is obtained.
  • the solid material feed comprising uranium and/or scandium, at least one of nickel and cobalt, and at least one of iron and aluminium, is leached in a mineral acid selected from H2SO4, HCI, and HNO3 or mixtures thereof in an aqueous medium.
  • a mineral acid selected from H2SO4, HCI, and HNO3 or mixtures thereof in an aqueous medium.
  • said mineral acid is H2SO4 or HCI, and more preferably, said mineral acid is H2SO4, because it allows for the straightforward formation of nickel sulphate and cobalt sulphate, respectively, and since sulphuric acid is more easily handled.
  • the feedstock used in the process can be any raw material that comprises uranium and/or scandium, at least one of nickel and cobalt, and at least one of iron and aluminium.
  • the solid material feed material may contain 1 to 1000 ppm uranium, relative to the total dry weight of the solid material feed, or 1 to 100 ppm uranium, or 5 to 100 ppm uranium, or 10 to 70 ppm uranium.
  • the solid material feed may contain 1 to 5000 ppm scandium, relative to the total dry weight of the solid material feed, or 1 to 1000 ppm scandium, or 5 to 750 ppm, or 10 to 550 ppm scandium.
  • the solid material feed typically contains at least 20 wt% of at least one of nickel and cobalt, relative to the total dry weight of the solid material feed, more preferably at least 25 wt%, even more preferably at least 30 wt%, and less than 60 %, more preferably less than 53 wt%.
  • the solid material feed typically contains at least 0.05 wt% of at least one of iron and aluminium, relative to the total dry weight of the solid material feed, more specifically at least 0.09 wt%, even more specifically at least 0.2 wt%, and less than 10 wt%.
  • the solid material feed may comprise one or more other impurities whereby said impurities comprise one or more selected from the list comprising Cu, Zn, Mn, Li, F, C, Ca, Si, P, As, Cd, Sb and Mg.
  • the preferred feedstocks are mixed hydroxide precipitate (MHP) and cobalt hydroxide precipitate (CHIP).
  • said mixed hydroxide precipitate (MHP) contains 5 to 100 ppm U, relative to the total dry weight of said mixed hydroxide precipitate.
  • said mixed hydroxide precipitate (MHP) contains 5 to 550 ppm Sc, relative to the total dry weight of said mixed hydroxide precipitate.
  • said mixed hydroxide precipitate comprises nickel in an amount of 25 to 60 wt.%, relative to the total dry weight of said mixed hydroxide precipitate, preferably in an amount of 33 to 53 wt.%.
  • said mixed hydroxide precipitate comprises cobalt in an amount of at least 0.1 wt.%, relative to the total dry weight of said mixed hydroxide precipitate, preferably in an amount of at least 0.2 wt.%, and more preferably in an amount of 0.9 to 6.0 wt.%.
  • said mixed hydroxide precipitate comprises manganese in an amount of at least 0.001 wt.%, relative to the total dry weight of said mixed hydroxide precipitate, preferably in an amount of at least 0.01 wt.%, and more preferably in an amount of 0.1 to 7.0 wt.%.
  • said mixed hydroxide precipitate comprises carbon in an amount of 0.01 to 5.00 wt.%, relative to the total dry weight of said mixed hydroxide precipitate, more preferably in an amount of 0.01 to 3.00 wt.%, and more preferably in an amount of 0.01 to 1.00 wt.%.
  • said mixed hydroxide precipitate comprises zinc in an amount of 0.01 to 0.30 wt.%, relative to the total dry weight of said mixed hydroxide precipitate.
  • said mixed hydroxide precipitate comprises iron in an amount of 0.1 to 3.0 wt.%, relative to the total dry weight of said mixed hydroxide precipitate.
  • said mixed hydroxide precipitate contains 0.1 to 3.0 % Al, relative to the total dry weight of said mixed hydroxide precipitate.
  • said mixed hydroxide precipitate comprises water in an amount of 25 to 60 wt.%, relative to the total wet weight of said mixed hydroxide precipitate, preferably in an amount of 30 to 55 wt.%.
  • the leaching process can be performed at a temperature ranging from ambient to 100°C, preferably from 70 to 95°C, and at a pressure ranging from atmospheric to 10 bar, preferably from atmospheric to 5 bar.
  • the leaching process can also be performed in the presence of a reducing agent to increase the leaching yield.
  • the reducing agent can be selected from a variety of reducing agents, such as sulphur dioxide, hydrogen peroxide, hydrazine, and hydroxylamine.
  • step ii . the pH of the leachate solution obtained from step i. is increased to at least 2.5 by adding a base to the solution, thereby precipitating iron and/or aluminium and more preferably to a pH between 2.5 and 7.0 or between 3.0 and 6.0, and even more preferably between 2.5 and 5.0 or between 3.0 and 5.0, and most preferably at a pH of about 3.0, 3.5, 4.0, 4.5 or 5.0, or any value there in between.
  • the base used can be any suitable inorganic or organic base, preferably an inorganic base selected from the group consisting of potassium hydroxide, potassium carbonate, nickel hydroxide, nickel carbonate, cobalt hydroxide, cobalt carbonate, manganese hydroxide, manganese carbonate, calcium hydroxide, calcium carbonate, sodium hydroxide, sodium carbonate, lithium hydroxide, lithium carbonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, or a combination of two or more of the aforementioned. More preferably, said base is NaOH, KOH, CaOHz, or NiCOs, or a combination thereof.
  • the preferred bases are Ca(OH) 2 and NiCOs.
  • the precipitate containing iron and/or aluminium can be optionally filtered off from the leachate solution.
  • the leachate solution obtained from step i. is processed in a multi-step sequence, whereby the pH of the leachate solution is first increased in step ii.(a) to a pH between 2.5 and 4.5, preferably to a pH between 3.0 and 4.5, more preferably between 3.5 and 4.5, and most preferably to a pH of about 4.
  • the increase in pH effects the selective precipitation of iron and aluminium compounds while nickel and cobalt ions remain in solution.
  • the precipitate comprising iron and/or aluminium which is formed in step ii. may be filtered off from the basified leachate solution either in part or entirely prior to adding a phosphate compound in step iii. Removing the precipitate at least in part provides the advantage that the final precipitate which is filtered off in step iv. has a higher content of uranium and/or scandium which improves the efficiency of the subsequent uranium and/or scandium recovery. Yet, in a preferred embodiment, the precipitate comprising iron and/or aluminium which is formed in step ii. is not filtered off from the basified leachate solution prior to adding a phosphate compound in step iii.
  • step ii. uranium, if present, will predominantly remain in the leachate solution.
  • the amount of scandium ions, if present, in the leachate solution precipitated in step ii. is between 5 and 60 % of the scandium atoms present in the leachate solution.
  • a phosphate compound is added to the leachate solution obtained in step i. and/or to the basified leachate solution obtained in step ii. to form a uranium and/or scandium precipitate.
  • the phosphate compound used can be selected from the group consisting of H3PO4, HZPOT, HPC 2 ', and PO 3 '.
  • the phosphate compound is added in a stoichiometric excess of 10 to 1000 times, preferably 25 to 500 times the amount of uranium ions in the leachate solution obtained in step i. and/or in the basified leachate solution obtained in step ii., preferably 50 to 300 times the amount of uranium ions, and most preferably about 100, 150 or 200 times the amount of uranium ions.
  • the phosphate compound may be added in a stoichiometric excess of 5 to 1000 times, preferably 10 to 1000 times, preferably 15 to 500 times the total amount of uranium ions and scandium ions in the leachate solution obtained in step i., preferably 15 to 500 times the total amount of uranium ions and scandium ions in the leachate solution, and most preferably about 100, 150 or 200 times the total amount of uranium ions and scandium ions in the leachate solution
  • the uranium and/or scandium precipitate is then filtered off from the leachate solution in step iv. If the precipitate containing iron and/or aluminium was not previously filtered off from the leachate solution prior to step iii., it can be filtered off in step iv. together with the uranium and/or scandium precipitate.
  • the process may be conducted in a single vessel, which simplifies the process and reduces costs.
  • the process is a continuous process.
  • the precipitate containing uranium and/or scandium can then be subjected to a reduction process to recover the uranium and/or scandium.
  • the reduction process can include roasting the precipitate in air, followed by leaching with an acid to recover the uranium and/or scandium.
  • uranium is present in the solid feed material, 20 to 95 at.% of the uranium ions present in the basified leachate solution in step ii. are precipitated into the uranium precipitate of step iii., preferably at least 30 at.%, more preferably at least 55 at.%, preferably less than 90 at.%, more preferably less than 85 at.%.
  • the present invention includes in step v. the extraction of uranium and/or scandium from said aqueous solution obtained in step iv. into an organic phase comprising an extractant and a diluent, thereby obtaining an uranium and/or scandium -enriched organic phase, respectively and an aqueous raffinate containing at least one of nickel ions and cobalt ions.
  • cobalt is extracted to the organic phase, next to uranium and/or scandium and other impurities, such as manganese, calcium, zinc, copper and cadmium, in order to separate cobalt from nickel.
  • the present invention provides a process according to the first aspect of the invention, wherein said extraction in step v. is performed at a temperature between 20 and 45 °C, preferably at a temperature between 20 and 40 °C, even more preferably at a temperature between 25 and 35 °C. It was found that lower temperatures provide a better selectivity for Mn extraction, and thus better separation of Mn from Co. Preferably, said temperature is above 20 °C, or even above 25 °C to facilitate operational temperature settings under circumstances of high environmental temperature.
  • the solvent extraction step v. can be performed in any device suitable and is not specifically limited.
  • Solvent extraction equipment generally includes at least one or more devices consisting of a mixer-settler, a column contactor, a centrifugal contactor or any other type of contactor.
  • the extraction is performed in a counter-current configuration.
  • the present invention provides a process according to the first aspect of the invention, wherein said aqueous uranium and/or scandium, nickel and/or cobalt solution entering step v. has a pH between 1.0 and 5.0 before being contacted with said solvents comprising extractant, generating a chemical equilibrium between the aqueous nickel solution and the solvent, more preferably at a pH between 1.5 and 3.5, and most preferably at a pH between 2.0 and 3.0.
  • the present invention provides a process according to the first aspect of the invention, wherein said aqueous uranium and/or scandium, nickel and/or cobalt solution obtained in step iv. is acidified before entering step v.
  • the present invention provides a process according to the first aspect of the invention, wherein said organic phase used in step v. comprises said extractant in an amount of 5 to 50 vol.%, relative to the total volume of said organic phase, and said diluent in an amount of 50 to 95 vol.%, relative to the total volume of said organic phase. More preferably, said organic phase comprises said extractant in an amount of 30 to 40 vol.%, and said diluent in an amount of 60 to 70 vol.%.
  • the organic phase may comprise a modifier.
  • the present invention provides a process according to the first aspect of the invention, wherein said diluent is a hydrocarbon. More generally, any organic, water-immiscible solvent capable of dissolving the extractant can be used. Hence, the diluent is not specifically limited. As diluent examples, kerosenebased compounds, which can be aliphatic, naphthenic, aromatic or even mixtures thereof, can be used.
  • the present invention provides a process according to the first aspect of the invention, wherein said extractant used in step v. comprises alkylphosphorus-based extractants.
  • Alkylphosphorus-based acids act as chelating extractants due to the presence of coordinative oxygen atoms in these molecules.
  • an element that forms the corresponding chelate compound with a higher stability facilitates the extraction efficiency more compared to an element that is less likely to form the chelate compound.
  • Alkylphosphorus-based acids have a high selectivity for uranium and/or scandium, respectively, over nickel and cobalt.
  • Alkylphosphorus-based acid extractants may be chosen from, but are not limited to, the following options:
  • 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester also known as EHEHPA, HEHEHP, P507, PC88A
  • an organophosphorus compound with the formula R.1 (CsHi?) (C8Hi7O)PO2H,
  • phosphinic acids such as bis-(2,4,4-trimethylpentyl) phosphinic acid (also known as Cyanex 272, lonquest 290), an organophosphorus compound with the formula (C16H34)PO 2 H.
  • phosphine oxides such as trioctyl phosphine oxide.
  • phosphoric acids have the highest selectivity for uranium and scandium.
  • Such phosphoric acids can be used in their protonated form, but also as derivates thereof, including the alkali-metal-converted form, i.e. a phosphoric acid that is partially neutralized with an alkali metal hydroxide, and/or the form preloaded with cobalt, nickel or a mixture of nickel and cobalt. It was found that preloading of said extractant used in step v. with nickel and/or cobalt allowed for an optimal and improved extraction without loss of processability of the extractant.
  • the partially neutralized extractant i.e.
  • the alkylphosphorus-based extractant comprises an alkylphosphoric acid and/or derivatives thereof.
  • said alkylphosphorus-based extractant comprises an alkylphosphoric acid and/or conjugated bases thereof.
  • the alkylphosphoric acid is di-(2-ethylhexyl) phosphoric acid, and/or nickel or cobalt salts thereof.
  • the uranium and/or scandium-enriched organic phase obtained in step v. is treated with a first stripping fluid (Si).
  • all elements except uranium and scandium, and iron, if present, extracted in step v. into the organic phase are recovered from said organic phase after step v. using a first stripping fluid (Si).
  • a first stripping fluid Si
  • a first aqueous eluate (Ei) typically comprising, if present, manganese, calcium, zinc, copper and cadmium, while if present, uranium and scandium remain in the organic phase.
  • the uranium and/or scandium -enriched organic phase obtained in step v. is treated with a first stripping fluid (Si) and subsequently with a second stripping fluid (S2), thereby respectively obtaining a first aqueous eluate (Ei) and a second aqueous eluate (E 2 ).
  • the residual acid concentration of the stripping fluid after the second stripping step is higher than that after the first stripping step, whereby said residual acid concentration is measured at the final contacting stage of the organic phase with the respective stripping fluid, i.e., the stage where the aqueous stripping fluid leaves the stripping section in a counter-current configuration.
  • the aqueous stripping fluid after stripping is also called the eluate.
  • the acid concentration of the second eluate solution (E 2 ) is higher than that of the first eluate solution (Ei).
  • said first and second stripping fluid are one or more selected from the group comprising: hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, phosphoric acid, sulphuric acid, boric acid and perchloric acid. More preferably, said first and second mineral acid are selected from sulphuric acid, hydrochloric acid, and phosphoric acid.
  • said first stripping fluid (Si) has an acid concentration of 0.5 M to 5 M.
  • An "acid concentration" of the stripping fluid as used herein refers to the initial acid concentration of the stripping fluid, namely measured at the initial contacting stage of the organic phase with the stripping fluid.
  • said first stripping fluid comprises a sulphuric acid concentration of at least 50 g/L, more preferably at least 100 g/L, preferably less than 500 g/L, more preferably less than 250 g/L.
  • said first stripping fluid (Si) comprises an hydrochloric acid content of at least 18 g/L, more preferably at least 36 g/L, and preferably less than 182 g/L, more preferably less than 91 g/L.
  • said first stripping fluid comprises a phosphoric acid concentration of at least 50 g/L, more preferably at least 100 g/L, preferably less than 500 g/L, more preferably less than 250 g/L.
  • said second stripping fluid (S2) has an acid concentration of 2 M to 10 M.
  • the upper limit of the concentration of the second stripping fluid is determined by the stability of the extractant in the acid conditions.
  • said second stripping fluid (S2) comprises a sulphuric acid concentration of at least 200 g/L, more preferably at least 250 g/L, most preferably at least 500 g/L, and preferably less than 1000 g/L, more preferably less than 800 g/L.
  • said second stripping fluid (S2) comprises an hydrochloric acid concentration of at least 75 g/L, more preferably at least 100 g/L, most preferably more than 180 g/L, preferably less than 350 g/L, more preferably less than 250 g/L.
  • said second stripping fluid (S2) comprises a phosphoric acid concentration of at least 200 g/L, more preferably at least 250 g/L, most preferably at least 500 g/L, and preferably less than 1000 g/L, more preferably less than 800 g/L.
  • the acid concentration of the second stripping fluid (S2) is higher than that of the first stripping fluid (Si).
  • the stripping step can be performed in any device suitable and is not specifically limited.
  • Stripping equipment generally includes at least one or more devices consisting of a mixer-settler, a column contactor, a centrifugal contactor or any other type of contactor.
  • stripping with the first stripping fluid is performed in a counter-current configuration.
  • the present invention provides a process according to the first aspect of the invention, wherein stripping of the organic phase with the first and second stripping fluid is performed at a temperature between 20 and 55 °C, preferably at a temperature between 20 and 45 °C, more preferably at a temperature between 25 and 40 °C, most preferably at a temperature of about 25 °C, 30 °C, 35 °C, or 40 °C, or any value there in between.
  • the present invention provides a post-treatment step according to the first aspect of the invention, wherein said uranium and/or scandium -rich organic phase after the first stripping, when performed with hydrochloric acid, is additionally washed with sulphuric acid. Washing with sulphuric acid allows for the removal of residual chloride ions and possibly residual extracted metals other than uranium and scandium from the solvent.
  • the present invention provides a process according to the first aspect of the invention, wherein nickel and cobalt are scrubbed from said uranium and/or scandium-rich organic phase, before stripping with the first and second stripping fluid.
  • nickel and cobalt are scrubbed from said uranium and/or scandium-rich organic phase, before stripping with the first and second stripping fluid.
  • an acidic solution such as a sulphuric acid solution in water.
  • Nickel and cobalt are selectively scrubbed by applying optimal conditions of pH, specifically the acidity of the final scrub solution, and the added amount of acid is adapted to reach this required pH.
  • the stripping of the organic phase is performed continuously using the first stripping fluid (Si), while only periodically, the second stripping fluid (S2) is used to remove uranium and/or scandium from the organic phase. More specifically, the second stripping fluid is applied to the organic phase when the concentration of uranium and/or scandium in the organic phase is higher than 0.5 g/L, more specifically higher than 1 g/L, even more specifically higher than 2 g/L. In this way, the accumulation of uranium and/or scandium on the organic phase is stopped, and the solvent extraction capacity of the organic phase is controlled.
  • the second, uranium and/or scandium-enriched aqueous eluate (E 2 ) obtained after stripping said organic phase with a second stripping fluid (S 2 ) is re-introduced upstream in the process, more preferably it is reintroduced before step ii., and most preferably it is re-introduced to step i. More specifically the re-introduction of the aqueous eluate (E 2 ) to step i. has the advantage that the acid is used for leaching.
  • the second stripping fluid (S2) is hydrochloric acid, and the aqueous eluate (E 2 ) is re-introduced to step i.
  • a CHIP product is provided with a composition according to Table 2.
  • CHIP is leached in a reactor comprising water and a 1 : 1 mixture of hydrochloric acid and sulphuric acid.
  • the pH of the solution is increased to 4.2 by slowly adding nickel carbonate.
  • a precipitate comprising iron and aluminium is formed while nickel and uranium remain in solution.
  • NaH 2 PO4 is added to the eluate to form a precipitate of uranium in the leachate.
  • the precipitate containing uranium is then filtered off.
  • the uranium precipitate is subjected to a reduction process to recover the uranium. Analysis of the filtrate indicated that the amount of uranium is reduced by about 60%, relative to the uranium content in said CHIP.
  • An MHP product is leached, and after precipitating iron, aluminium and part of the uranium, a solution with the following composition is obtained, and provided as a feed to a solvent extraction process for further purification:
  • An MHP feed is continuously leached, purified from iron and aluminium and uranium by precipitation and solvent extraction.
  • the organic phase is stripped with a first stripping fluid, and the uranium-enriched solvent is re-used for extraction.
  • a treatment with a second stripping fluid is applied as follows:
  • a one-stage batch process is executed to strip an organic phase composed of 30 vol% D2EHPA with Escaid 110 as a diluent, at an O/A of 1 and a temperature of 40 °C.
  • the initial uranium concentration on the solvent, acid concentration of the second stripping fluid, and the percentage of uranium transferred to the aqueous eluate are the following:
  • An MHP product comprising nickel, cobalt, iron, aluminium and uranium is leached, and after precipitating iron, aluminium and part of the uranium with a phosphate compound, the solution is provided as a feed to a solvent extraction process using tri-n-butyl phosphate as an extractant.
  • This extractant enables a further reduction of the uranium content.
  • An MHP product comprising nickel, cobalt, iron, aluminium, uranium and scandium is leached, and after precipitating iron, aluminium and part of the uranium and scandium with a phosphate compound, the solution is provided as a feed to a solvent extraction process using PC88A as an extractant.
  • This extractant enables a significant further reduction of the uranium and scandium content.

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Abstract

La présente invention concerne un procédé respectueux de l'environnement pour l'élimination de l'uranium et/ou du scandium dans des ressources contenant du nickel et/ou du cobalt, comprenant les étapes consistant à : i. lixivier une charge de matériau solide comprenant de l'uranium et/ou du scandium, et au moins 20 % en poids de nickel et/ou de cobalt, avec un acide minéral dans un milieu aqueux, ce qui permet d'obtenir une solution de lixiviat comprenant des ions uranium et/ou scandium, et des ions nickel et/ou des ions cobalt ; ii. faire précipiter au moins en partie l'uranium et/ou le scandium en ajoutant un composé de phosphate et en amenant le pH de ladite solution de lixiviat à au moins 2,5, et séparer le précipité du milieu aqueux ; iii. extraire l'uranium et/ou le scandium restant à partir du filtrat aqueux obtenu à l'étape ii. dans une phase organique comprenant un agent d'extraction et un diluant, ce qui permet d'obtenir un raffinat aqueux comprenant des ions nickel et/ou des ions cobalt.
PCT/EP2025/058339 2024-03-27 2025-03-26 Procédé respectueux de l'environnement permettant d'éliminer l'uranium et/ou le scandium de ressources contenant du nickel et/ou du cobalt Pending WO2025202333A1 (fr)

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EP24167018.1A EP4624602A1 (fr) 2024-03-27 2024-03-27 Procédé sans danger pour l'environnement pour éliminer l'uranium de ressources contenant du nickel et/ou du cobalt
EP24167018.1 2024-03-27
EP25151296 2025-01-10
EP25151296.8 2025-01-10

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB759900A (en) 1949-01-11 1956-10-24 Atomic Energy Authority Uk Improvements in and relating to the production of uranium
WO2010118455A1 (fr) 2008-04-18 2010-10-21 Enfin Australia Pty Ltd Procédé pour le traitement de produit hydroxyde mélangé produit dans un processus d'extraction de métal
US20160289795A1 (en) * 2015-02-10 2016-10-06 Scandium International Mining Corporation Systems and Processes for Recovering Scandium Values From Laterite Ores
WO2022090628A1 (fr) 2020-10-30 2022-05-05 Kemira Oyj Extraction de cobalt

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB759900A (en) 1949-01-11 1956-10-24 Atomic Energy Authority Uk Improvements in and relating to the production of uranium
WO2010118455A1 (fr) 2008-04-18 2010-10-21 Enfin Australia Pty Ltd Procédé pour le traitement de produit hydroxyde mélangé produit dans un processus d'extraction de métal
US20160289795A1 (en) * 2015-02-10 2016-10-06 Scandium International Mining Corporation Systems and Processes for Recovering Scandium Values From Laterite Ores
WO2022090628A1 (fr) 2020-10-30 2022-05-05 Kemira Oyj Extraction de cobalt
CA3196776A1 (fr) * 2020-10-30 2022-05-05 Ruan PRETORIUS Extraction de cobalt

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Title
"Atlas of Electrochemical Equilibria in Aqueous Solutions", 1 January 1974, article POURBAIX: "Pourbaix diagrams for Fe, Al, U and Co", XP093061334 *
KIEGIEL, K.ABRAMOWSKA, A.BIETUSZKA, P.ZAKRZEWSKA-KOTTUNIEWICZ, G.WOTKOWICZ, S.: "Solvent extraction of uranium from leach solutions obtained in processing of Polish low-grade ores", JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY, vol. 311, 2017, pages 589 - 598, XP036127811, Retrieved from the Internet <URL:https://doi.org/10.1007/s10967-016-5029-5> DOI: 10.1007/s10967-016-5029-5
YAGMURLU BENGI ET AL: "Effect of Aqueous Media on the Recovery of Scandium by Selective Precipitation", METALS, vol. 8, no. 5, 3 May 2018 (2018-05-03), CH, pages 314, XP055837325, ISSN: 2075-4701, DOI: 10.3390/met8050314 *

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